BS 6229:2025 is the updated UK code of practice for flat roofs with continuously supported flexible waterproof coverings, released 31st December 2025.
It modernises industry expectations for the design, installation, inspection, drainage, thermal performance, fire safety, and maintenance of flat roofs and expands the definition of a blue roof to allow for absolute zero falls with no back falls, bringing it in line with other industry guidance such as CIRIA Blue Roofs – a guide to implementation (C817) 2024.
The GRO (Green Roof Organisation) Code of Best Practice is the UK’s primary guidance for green roofs and, in its latest editions, incorporates blue roof and biosolar roof applications. It is a best‑practice framework covering design, specification, installation, and maintenance. ABG were involved in the technical committee for the latest edition and the Leeds Skelton Lakes Extensive Green Roof Project is featured on the cover.
The German FLL Guidelines (Forschungsgesellschaft Landschaftsentwicklung Landschaftsbau e.V.) are the world’s most influential technical standard for green roofs. They provide detailed engineering, ecological, and performance requirements for green roof systems.
CIRIA Blue Roofs – a guide to implementation (C817) 2024, published November 2024, is a dedicated technical guide produced by CIRIA to support the planning, design, installation, evaluation, and maintenance of blue roofs. ABG were members of the Susdrain project steering team that authored the new manual.
Schedule 3 of the Flood & Water Management Act is a legislative framework making Sustainable Drainage Systems (SuDS) mandatory for many new developments in England. Developers need to obtain approval from the relevant SuDS Approval Body (SAB) before connection to public sewers is permitted.
Sustainable Drainage Systems (SuDS) are a collection of water‑management practices designed to mimic natural drainage processes and manage rainfall as close as possible to where it lands.
They represent a shift away from traditional piped drainage, which rapidly conveys water to sewers, towards systems that slow, store, filter, and infiltrate water in a more sustainable way.
The CIRIA SuDS Manual (C753) is the UK’s most comprehensive and authoritative guidance document on the planning, design, construction, operation, and maintenance of Sustainable Drainage Systems (SuDS). ABG were asked to provide feedback and expertise in relevant subject areas throughout the development of the manual.
NFRC technical guidance for the design and construction of blue roofs was, at the time of publication, the UK roofing industry’s primary technical guidance for the design and installation of blue roofs. It was created since there was no British or European Standard covering blue roofs at the time. The more recent publication of CIRIA Blue Roofs – a guide to implementation (C817) 2024 now supersedes earlier advisory documents, including the NFRC guidance.
BREEAM (Building Research Establishment Environmental Assessment Method) is the world’s longest‑established and one of the most widely used sustainability assessment methods for buildings. It evaluates the environmental, social, and economic performance of buildings across their entire life cycle. The use of Blue and Green Roofs contribute towards BREEAM credits. BREEAM is more common within the UK than LEED.
LEED (Leadership in Energy and Environmental Design) is a globally recognised green building rating system developed by the U.S. Green Building Council (USGBC). It provides a framework for designing, constructing, operating, and certifying high‑performance, sustainable buildings.
ISO 9001 is the international standard for Quality Management Systems (QMS), published by the International Organization for Standardization (ISO). It sets out the globally agreed requirements an organisation must meet to prove it can consistently deliver products and services that satisfy customer expectations and regulatory obligations. ABG has an externally certified Business Management System complying with ISO 9001 & ISO 14001, with a scope covering the design, development, manufacture, stockholding and supply of environmental geosynthetics, drainage, attenuation, erosion and ground control products and solutions.
ISO 14001 is the International standard for Environmental Management Systems. It helps organisations manage their environmental impacts, comply with legal requirements, prevent pollution, and improve environmental performance over time.
The London Plan 2021 is the Mayor of London’s statutory spatial development strategy for Greater London. Adopted on 1 March 2021, it sets out policies that guide planning decisions, development standards, sustainability expectations and climate‑resilience requirements across all London boroughs. The plan explicitly supports and prioritises the use of blue roofs.
Dublin City Council Green & Blue Roof Guide 2021 is a formal guidance document published to support the implementation of green and blue roofs across Dublin.
It sits within DCC’s wider Sustainable Drainage (SuDS), climate‑action, biodiversity, and development‑planning framework and provides mandatory design expectations for new developments.
FEH13 (Flood Estimation Handbook 2013) is the 2013 update to the Flood Estimation Handbook rainfall model providing rainfall depth-duration-frequency (DDF) estimates and catchment descriptors for hydrological modelling across the UK. FEH22 is the most recent rainfall DDF model released in December 2022. FEH22 maintains the methodology of FEH13 but using enhanced data sets.
FSR (Flood Studies Report 1975) is the original nationwide UK rainfall and flood estimation methodology using rainfall data from 1941 to 1970.
BROOF(t4) is the highest external fire‑performance classification for a roof system under the European Standard BS EN 13501‑5.
It means the entire roof build‑up (not just one product or layer) has passed the EN 1187 Test 4 – the most severe of the European roof fire tests. It assesses fire spread across the roof and fire penetration through the roof.
Green roofs can comply if correct substrate depth, organic content limits, and fire breaks are used.
Blue roofs must ensure the underlying waterproofing and the total roof build-up match a BROOF(t4)‑tested system.
A SuDS Approval Body (SAB) is a local‑authority body responsible for approving Sustainable Drainage Systems (SuDS) for new developments. It was created under Schedule 3 of the Flood and Water Management Act 2010 to ensure that surface‑water drainage is designed, built, and maintained to national standards.
A sponge city is an urban design approach where the city is built to absorb, store, and naturally release rainwater—much like a sponge.
Instead of relying only on traditional drainage systems, sponge cities use features such as:
These help reduce flooding, improve water quality, recharge groundwater, and create greener, more resilient urban environments.
Biodiversity Net Gain (BNG) is a mandatory requirement in England under the Environment Act 2021, forcing developers to deliver a minimum 10% increase in biodiversity value for most new development projects. It ensures habitats are left in a better state than before, with improvements maintained for at least 30 years through on-site, off-site, or statutory credit solutions.
Welcome to the ABG Building Solutions website for Blue & Green roof systems, to visit the main ABG Geosynthetics site please go to:
www.abg-geosynthetics.com